This invention relates to human monoamine oxidase A and to recombinant DNA techniques.
Monoamine oxidase (monamine: O.sub.2 oxidoreductase, EC 1.4.3.4.; MAO) catalyzes the oxidative deamination of a wide variety of dietary amines and neurotransmitters such as dopamine, norepinephrine, and serotonin. It is an integral protein of the outer mitochondrial membrane and is present in all types of cells. Two isoenzymic forms (Types A and B) have been identified and are believed to consist of similar but non-identical proteins.
MAO has been implicated in a number of neurophysiological disease states, and MAO inhibitors have been used as antidepressants. MAO-B metabolizes the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to an active form which elicits Parkinsonian symptoms (Markey et al., 1984). Lower than normal levels of MAO activity have also been described in patients with various psychiatric disorders.
Human MAO-A and MAO-B are probably encoded by separate genes, which are closely linked on the X chromosome. A submicroscopic deletion in the Xp11.3 region of the human X chromosome results in the loss of both MAO-A and MAO-B activity in humans.